In various traffic situations some form of communication between a vehicle and an installation in a passage place can be required. Such communication can be a check that the vehicle is authorized to pass the checkpoint or a recording that a definite vehicle has passed at a particular time. Another frequent situation for communication involving a vehicle includes that an operation for collecting/recording a fee is performed, where the fee can be a toll fee for passing a particular road section, a bridge or a tunnel or a fee for accessing a parking area. The invention is in particular related to communication for collecting fees.
Such checkpoints exist which are provided with service personnel, a checking guard and a paying station for paying the fee. Also partly automated systems exist in which the vehicle driver possesses some identifying means which can be read in the checkpoint. In an operation for paying the fee it is then common that the driver has a magnetic card which is inserted and read in an automatic device which records the fee on an account in order to charge the owner of the card.
These systems are described as examples require the vehicle to stop in order to make it possible to perform the operation. However, there is a desire to avoid such stops in order to obtain a more flexible traffic flow. Thus, systems have been devised which work using remote sensing of an identifying means carried by the vehicle. Then often transponder methods are used which include that the checkpoint is provided with an active radio transmitter/receiver and that the vehicle is provided with a similar passive device which is arranged to receive the signal carrying codes from the radio equipment of the checkpoint, modulate it in order to carry a response message and retransmit it to the radio equipment of the checkpoint. Such a passive transmitter/receiver is called a transponder and provides as a response signal in its simplest shape only an identification of the vehicle. However, it can be expanded in order to store and process further data in an advanced manner so that also relatively complicated paying operations can be executed. They then include that after an identifying operation it is communicated that the fee can be drawn from an account set up for the purpose or from the balance of electronic money stored in the transponder and also further operational steps can exist. A system of this kind is described in U.S. Pat. No. 4,303,904 to Chasek.
For such operations based on stored data and programs sometimes the transponder is connected to a computer which most advantageously has the shape of a so-called smart card, thus a minicomputer in the shape of a card, which can be inserted in a reader connected to or accommodated in the transponder unit. This arrangement has in particular the advantage that the same transponder can be used for different purposes and by different users of the vehicle, thereby including a selective recording of fees and other data for the respective user.
Such an arrangement will then be physically complicated and has a higher cost than arrangements including only a transponder even if it is provided with a relatively large storage and processing capacity. Therefore, it has appeared that a need exists for an intermediate shape of the transponders that are used today and that do not allow the described selective operation in a secure way. The need also exists to supplement the more complicated shape including the transponder with a separate data carrying unit, such as a smart card.